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%I #9 Aug 11 2024 14:41:34
%S 1,55,171,3003,15051,617716,1269621,35133153,178727871,1264114621,
%T 13953435931,0,1313207023131,19895044059891,114401848104411,
%U 1250444114440521,11121736463712111,357961407704169753
%N Smallest n-digit palindromic triangular number, or 0 if no such number exists.
%H P. De Geest, <a href="https://www.worldofnumbers.com/em_alltria.htm">Exhaustive list of Palindromic Triangulars</a>
%e a(4) = 3003 = 77*78/2 is the smallest 4-digit palindromic triangular number.
%e a(12) = 0 as no 12-digit palindromic triangular number exists.
%Y Cf. A068642, A068643, A068644, A000217, A003098, A008509, A008510, A054263.
%K base,nonn
%O 1,2
%A _Amarnath Murthy_, Feb 28 2002
%E Edited by _Patrick De Geest_, Mar 24 2002